Self-opening die head



April 16, 1940.

A. F. BREITENSTEIN SELF-OPENING DIE HEAD 3 Sheets-Sheet 1 9 l 3. e m J d n 7 m, MZ/v5 ooh M5. ou ,.0

u. A w m w April 16, 1940- A, F. BREITENSTEIN 2,197,336

SELF-OPENING DIE HEAD 5 Sheets-Sheet 2 Filed June 3, 1939 All'l'l 16, l940 A. F. BREITENSTEIN l 2.197.336

SELF-OPENING DIE HEAD Filed June 3, 1939 3 Sheets-Sheet 3 Patented Apr. 1 6, 1940 SELF-OPENING DIE HEAD Albert F. Bretenstein, New Haven, Conn.; assignt or to The-Geometric ToolQompany, New Haven, Conn., a corporation of Connecticut Application June 3, 1939, Serial No. 217,148 16 Claims. `(Cl. lll-F96) The present invention relates to improvements in self-opening die heads. More particularly, the

present invention relates to improvements in self opening die heads of the type employing an oscillating Chaser-operating member.

One of the objectsof the present invention is to provide a superior self -opening die head of the character above referred to, and which is reliable in its operation and economical to produce and V maintain. l t

Another object of the present invention is Vto provide a superior self-opening die head of the type above referred to, and characterized by such a degree of compactness as will'enablevthe die 1 5 head to be used in confined and limited spaces.

A further object of the present invention is to provide a superior die head of the type referred to and which may be relied upon to accurately and uniformly retire its chasers from the work at a 20 predetermined pointthereon during repeated cycles of operation of the die head.

With the above and other objects in view, as will appear to those skilled in the art from the present disclosure, this invention includes all features in g5 the said disclosure which are novel over the prior art.

In the accompanying drawings, in whicheertain modes of carrying out the present invention are shown for illustrative purposes:

3 0 Fig. 1 is a view in side elevation of a self-opening die head embodying the present invention;

Fig. 2 is a vfront-face view thereof;

Fig. 3 is a rear-face view thereof;

Fig. 4 is a longitudinal sectional view thereof 35 taken on the line 4 4 of Fig. v2 and illustrating the parts in the positions which they assume when the chasers are in their advanced or thread-cutting positions;

Fig. 5 is a view corresponding to Fig. 4,-but illus- 40 trating the parts in the positions due to .them at the instant that the latch-member reaches a position to permit the chasers to be retired out; of

engagement with the work;

Fig. 6 is a fragmentary sectional view taken on 4.5 the line 6 6 of Fig. 1;

Fig. 7 is a transverse sectionalview taken on the line 'I 'e' of Fig. 4;

Fig. 8 is a similar view taken on lthe line 8 8 of Fig. 4;

50 Fig. 9 is a view in central-longitudinal section taken on the line 9 9 of Fig. 2, but showing the position which the parts assume at the instant that the latch-member reaches its releasing position as ,a result of the forward movement of the 5 chaserfcarrying `.member and associated parts erally designated by the reference character 25.

with respect to 4the mounting-memberwhich movement has been effected by forward draft exerted upon the chasers by the Work being threaded;

. Fig. l0 is a perspective view of the inountn-g- 5' l member; y

. Fig.l 11. is a perspectiveview of the L-shaped latch-member;A ,y

Fig. 12 is a transverse sectional view taken on the line I2 i2 of Fig. '7; Fig. 13 is`atransversesectional view taken on the line 13 l3 of Fig. 8; n r

Fig. 14 is a broken view in transverse. sectionv taken on the `line M M of Fig. V7; and

Fig.l 15 is a similar view taken on thevlin'e l5 l5 1 51 ofA Fig. 7. y

The particular self-opening die head vherein chosen for the illustration of the present invention, 4 includes al mounting-member generally designated by the vreference character vand in. 20 .cluding a rearwardly-extending tubular shank 2| which is adapted to be mounted in the turret or other yappropriate featureof asc'rew-machine or lthe like. The saidy shank 2l is preferably formed integral with, and projects rearwardly from, av

plate-dike vbody-portion 2,2 from the front portion of whichylatterforwardly extends a tubular guide- Aportieri 23.V Thesaid guide-portion ,2t-extends with a close sliding fit into ,an axial rbearing-passage 22 formed in a chasercarrying member genl"0 Iif forwardly-projecting from -an oscillating Chaser-operating ring 3B.

The said oscillating Chaser-operating ring is mounted with capacity for oscillating movement upon .the centraleportion .of the chaser-carrying 'member 25 and is retained in place thereon against rel-ativerearward displacement Abyv a 'rego taining-plate 3l; The said retaining-plate -31 is secured to the said Chaser-'carrying member 25 by means oftwo (more .or less) screws 32 32 as is shown in Figs. 3 .and 12. The said retainingi plate 3| 'is centrallyaperturedto receive van .an-y 55 nular locating-flange 33 projecting rearwardly from the Chaser-carrying member 25 and having 3| and hence the Chaser-carrying member 25 and associated parts, to the mounting-member 2li, the. body-portion 22 of the said mounting-member is provided with two (more or less) coupling-pins 34-34 as is shown particularly well in Figs. 8 and I 13. The said coupling pins 34-34 project forwardly from the body-portion 22 of the mounting-l member and extend with aclose sliding t respectively, into the adjacent one of two corresponding coupling-passages 35-35 extending from front to rear through the retaining-plate 3| adjacent the outer periphery thereof.

From the foregoing it will be seen that the interfitting of the coupling-pins 34-34 and the coupling-passages 35-35 will serve to couple the mounting-member 2li to the retaining plate 3| and hence also to the Chaser-carrying member and the parts carried thereby. Relative axial movement is, however, provided for between the coupling-pins 34-34 and the coupling-passages 35-35 for the purpose as will more fully hereinafter appear.

To normally but yieldingly hold the chasercarrying member 25 and the parts carried thereby in their rearmost positions with respect to the mounting-member 23, two (more or less) retracting-springs 36-36 are respectively located in spring-pockets 31-31 formed partly in the chaser-carrying member 25 and partly in the retaining-plate 3| carried by the said Chaser-carrying member, as is shown particularly well in Fig. 14. The said retracting-springs 35--36 respectively encircle screw-studs 38-33 which are threaded into and project forwardly from the body-portion 22 of the mounting-member 28. Each of the retracting-springs 36-36, thrusts at its forward end, against the under face of the head of its complemental screw-stud 38 and thrusts, at its rear end, against the rear end-wall of the particular spring-pocket 31 in which the retracting-spring in question is loc-ated.

For the purpose of normally maintaining the rear face of the retaining-plate 3|, which forms a unitary part of the Chaser-carrying member 25, in spaced relationship with respect to the forward face of the body-portion 22 of the mounting-member 20, and to provide a cushioning action for the purpose as will more fully hereinafter appear, two helical cushioning-springs 39-39 are employed (Figs. '7 and 15). The said cushioning-springs 39-39 are respectively housed within spring-pockets 48-40 formed partly within the Chaser-carrying member 25 and partly within the retaining-plate 3|. The said cushioningsprings 39-39 each press against the front endwall of its complemental spring-pocket 4G as is shown in Fig. 15. The rear end of each of the cushioning-springs 39-39 respectively, thrusts rearwardly against a cushioning-plunger 4|', one of which latter is mounted with capacity for reciprocatory movement in each of the springpockets 4|i4|l. i

Each cushioning-plunger 4 |-4| above referred to, thrusts at its rear end against the forward face of the body-portion 22 of the mounting- Amember 20 and is formed with an annular stopflange 42 `which is normally engaged with the,

rear wall of the complemental spring-pocket 4|) to limit the rearward movement of the cushioning-plunger 4| of which itforms a part.

The retracting-springs 33-36 and the cushioning-springs 39-39 are preferably so proportioned in the elastic power which they provide,`

that the said cushioning-'springs 39-39 dominate the retracting-springs 36-36, whereby in the absence of extraneous forces the retracting-plungers 4|4| will always hold the rear face of the retaining-plate 3| in spaced relationship forwardly of the front face of the body-portion 22 of the mounting-member 20, despite the continued effort of the retracting-springs 36--35 to bring the two said faces together.

To provide for eliminating the cushioningaction provided for by the cushioning-springs 39 and associated parts, the body-portion 22 of the mounting-member 2B is provided near its periphery with a stop-sc-rew 43 extending in parallelism with the axis of the die head and adapted to be threaded forwardly to engage with the rear face of the retaining-plate 3| as is shown in Fig. 1 of the drawings. Extending perpendicularly with respect to the stop-screw 43 is a binding-screw 44 also mounted in the body-portion 22 of the mounting-member 20 and serving, when screwed home, to lock the stop-screw 43 in any given position of adjustment. l

In its rear portion, the Chaser-operating ring is formed with a rearwardly-opening annulargroove 45 in which is mounted a helical chaserretracting spring 46 as is especially well shown in Fig. '1. The said Chaser-retracting spring thrusts at one end against a stud 41 which is rigidly mounted in the retaining-plate 3| and which projects forwardly therefrom into the annulargroove 45 in'the rear face of the Chaser-operating ring 30, as will be seen by reference to Figs. 1 and 12 in particular. The opposite end of the chaserretracting spring 45 thrusts against a stud 48 rigidly mounted in the Chaser-operating ring 30 and projecting into the groove 45 therein, as will be seen by reference to Figs. 'l and 14 in particular.

As thus arranged, the Chaser-retracting spring 46-exerts a constant but yielding effort to turn the Chaser-operating ring 30 in the direction of the arrows 49 shown in Figs. 2 and 7, to thus cause the segmental inclined cam-lugs 29 to move the chasers 21 outwardly into their retired positions.

Rigidly installed in the rearwardly-opening annular-groove 45 of the Chaser-operating ring 3U, is a segmental latch-block 50 which is held in place by a pin 5| as is indicated in Fig. '7. One end of the latch-block 50 provides a latching abutment 52 which is adapted to be engaged by one side of a latching-pin or -abutment 53 rigidly secured to and forwardly projecting from the inner end of a plate-like arm 54 forming a part of an L-shaped latch-membergenerally designated by the reference character 55. The said latch-member 55 also includes a forwardly-projecting tubular arm 53 extending in substantial parallelism with the axis of thedie head and provided in its forward portion with a threaded bore 51 from the rear end of which extends a relatively small-diametered guide-passage 58. Threaded into the bore 51 in the tubular arm 55 of the latch-member 55 is a tripping-screw 59 having a nut-like head S0 formed integral therewith and located forwardly of the front end of the arm 56.

The tripping-screw 59 is axially adjustable with respectto the latch-member 55 and for the purpose of firmly locking the said tripping-screw in lthe lock-nut 6l. er 'iQ is adapted to reciprocate in a spring-pocket any given-position within its range of adjustment,`

the said tripping-screw'has threadedk onto it to the rearcf the head ga lock-nut 6l which is adapted to be jammed against the forwardjfacey of the arm 55 of the latch-member 55,-as is shown' The tripping-screw 59 is formed which normally receives a coupling-nut .66 having diametrical grooves S1 in its rear'face to receive a locking-pin '68 extending through the threaded rear-portion of the stem 62 upon which the coupling-nut 55 is mounted. The couplingnut 65 is also formed with a forwardly-projecting annular-sleeve 55 which may move freely through the passage B3 in the arm'fl before referred to.

; Encircling the forward portion of the tubular 'arm 56 of the L-shaped latch-member 55, is a tubular-spring-plunger 'I6 having a radially-ex-- tending annular ange 10a, and normally thrusting at its forward edge against the rear face of The said tubular spring-plung- 'H having its axis extending parallel with the axis of the die head and formed in a forwardlyextending tubular portion 12 of an L-shaped arm generally designated by the reference 'character '13 and formed integral with the retaining-plate 3l before referred to. Leading rearwardly from the spring-pocket H in the tubular portion 712 is a bearing-passage 4 extending through the rear face of the arm 'I3 and intersecting a radiallyextending recess 75 formed in both the rear face of the said arm 13 as well as in the rearface of the retaining-plate 3l proper. Leading forwardly from the inner end of the recess 'l5 just referred to in parallelism withthe bearing-passage '14, is a clearance passage T16 accommodating the latching-pin 53 and permitting the same to be extended forwardly into the rearwardlyfacing annular groove i5 in the Chaser-operating `ring 35, as is clearly shown' in the accompanying drawings.

Located in the rear portion of the springpocket 'H in the tubular portion 12 of the arm i3 is a helical latching-spring Tl. The said latchling-spring Tl encircles the tubular arm 55 of the latch-member 55 and thrusts at its forward end against the rear face of the tubular springplunger Ell and at its rear` end the said spring thrusts against the rear wall of the spring-pocket l. In this manner the latching-spring Tl exerts 1a constant but yielding effort to shift the entire latch-member 55 forwardly in a direction required to interpose the latch-pin 53 thereof into the path of movement of the latching-abutment52 carried by the Chaser-operating ring 30, as beforev described. l

For the purpose of limiting the oscillating movement of the Chaser-operating ring and to provide for releasing such restraint to a necessary degree, a radially retiralole` limiting-plunger` 18 is employed as is particularly well shown inFig. 6.

.The said limiting-plunger 78 is provided with a relatively-slender stem 19 and is mounted for reciprocatory movement in a housing 8B partly `threaded into the Chaser-operating ring 3i)A and partlyprojecting from-'the outerip'eripheryrf the Axially in line with the will hereinafter' be described.

latter'Tn'iimiting-piuriger '1a' is yyieldingiyV urged inwardly by a helical springl which en'- `circles' its stem A'1.9 V and which is enclosed Within thefhousing Mh The outerendof 'the stem '19 of the limiting-plunger ,18 is providedl with a'V peripherally-knurled iinger-piece 82xby means 'of whichV vthe limiting-plunger may bel drawn radially outwardly against the tension" of the spring 3L "The inner end of the limiting-plunger 'I8 enters an arcuate limiting-recess 831 formed in the outer surface of the Chaser-carrying member- Z5. yWhen the 'Chaser-operating ring" 30 is released to -the action of the chaser-retracting spring G6 in 'a manner as will hereinafter appear, the limiting-plunger la will be brought into engageirnent with the end-wall 84 of thelimitingmovement of the'isaid ring'fB.-

recess i3 'to thereby check thefurther turning By grasping the finger-piece 82 of the'limit ing-plunger 1S and drawing outwardly upon the:

same so-as to retire; the said plunger out ofthe limiting-recess 83,"the said chaser-operating ring may be turned to a further degree to completely disengage its cam-lugs 29 from the respective notches 28 in the chasers 21,'to vthus permit the radial removal of the said chasers from `the grooves 26 vin the Chaser-carrying member 25.

The die head structure herein shown is capable l of beingy tripped bytwo `distinct methods, i. e.

bythe relative forward draftexe'rted by the work upon the chasers 2l, and by the engagement of the head 60 of the tripping-screw "59 with a suitable abutment 1l5 l1"ig.` 5), all in a manner as With the parts positioned as is shown particularly well in Figs. 2 and 4, the die headis ready for a threading operation sincethe chasers 2f! are projected inwardly into their advanced or thread-cutting positions and the latch-pin 53' by its engagement with the latching-abutment 52 of the Chaser-operating ring 3l) serves to rigidly but releasably hold the said chasers in the position V referred to.

With the shank ZI of the mounting-member 25 l iirmly clamped in the turret of a screw-machine or other suitable holder, let it be assumedthat f the work to'be threaded is rotated with respect to `the die head structure which latter'is held stationary save for axial movement required to cngage its chasers 21 with the work.

Let it now be assumed that itis desiredto effect a tripping of the die head by means of an abutment such as the abutment lshown by broken lines in Fig. 5.; Under these conditionsas the die head structureis fed onto the work,I the head 60 of the tripping-screw 59 will, after apredefara termined axial travel of the die head, engage with the abutment 35 `(Fig. 5). Vl/henlthis occurs, the

` forward travelof the said' 'tripping-screw as wellf as the latch-member 55, `will be halted while the remainder of the diehead structure continuesr to 'move axially forwardly onto the work.. As the L die head structure (with thevv exception ofthe tripping-screw' and the parts connected thereto) continues its forward travel relativeto the work, the locking-abutment l52 carried by the Chaser-operating ring 30, will'move forwardly" out of engagement with the latching-pin 53. At

the instant the latching-abutment52 reaches the v position with respect to the laching-pin 55 shown in Fig. 5, the said latching-'abutment 52 and the ventire lcha'ser-operating ring .-39 will be freedl of restraint and theV chaser-retracting spring 45 will V act to turnV the said Chaser-operating ring in a engages with the endwall 8d ofthe-limiting-recess 83 (Fig. 6).

By the movement above described, 4the camlugs 29 of the chaser-operating ring 30 will have een moved in Aa clockwise direction and will, by

.by broken lines in `Fig. 2. The work just threaded and the die head may now be axially separated and the die head reset preparatory to another threading` operation.

work to the desired extent, the axial advance of The die head may be reset for another thread- 4ing operation by turning the Chaser-operating ring 35 in a counter-clockwise direction against the tension of the chaser-retracting spring d6, by means of force applied to a resetting-lug 86 rigid with and radiallyprojecting from the outer surface of the said Chaser-operating ring 30.

To effect the tripping of the die head by means of the work itself rather than by means of an extraneous abutment such as the abutment 85, the following procedure may be followed.

After the die head has been threaded onto the the mounting-member 20 with respect to the work may be halted. The continued rotary movement of the work represented by broken lines 87 lin Fig. 9 will, however, draw forwardly upon the chasers and hence upon the unit which comprises in the main, the chaser-carryng member 25, Chaser-operating ring 30 and retaining-plate 3l. Meanwhile, however, the tripping-screw 59 .and the parts rigid therewith will be held stationary by the engagement of the coupling-nut 6E with the bottom of the recess 65.

Ultimately the latching-abutment 52 carried by the chaser-operating ring 30 will move forwardly clear of the latching-pin 53 which is now held stationary, until the parts reach the positions in which they are indicated in Fig. 9 whereupon the chaser-retracting spring 46 will be free to turn the said ring and effect the retirement of the chasers 21' in the manner' before described.

As will be obvious from the foregoing, the tripping-point of ythe die head may be conveniently'adjusted by varying the position of the tripping-screw 59 with respect t0 the latch-member 55.

Attention may here be called to the fact that regardless of the mode of tripping utilized, the initial engagement between the chasers 21 and the Work may be cushioned, so to speak, by permitting free play to the cushioning-plungers 4l. If, for any reason, it should be desired to nullify this cushioning action, the stop-screw 43 may be projected into the position in which it is shown in Fig. l to normally engage the rear face of the retaining-plate 3l to thereby prevent the unit comprising the said retaining-plate, chasercarrying member 25 and Chaser-operating ring 36, from moving rearwardly further than as is indicated in Fig. l.

By providing a latch-member 55 or its equivalent and the associated parts, an extremely-rigid and precision-performing structure is provided which eliminates many of the objections to prior types of self-opening die heads.

The invention may be carried out in other specilc ways than those herein set forth without departing from the spirit and essential characteristics of the invention, and the present embodiments are, therefore, to be considered in all .respects as illustrative and not restrictive, and

all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.

I claim:

l. A self-opening die head including in combination: a chaser-carrying member; chasers movably mounted in the said Chaser-carrying member; an oscillating Chaser-operating member associated with the said Chaser-carrying member and operatively connected to the said chasers for controlling the movement thereof; spring-means urging the said Chaser-operating member into position to retire the said chasers; and a releasable L-shaped latch-member bodily movable with respect to the said Chaser-operating member and having a portion engageable with a portion of the latter to releasably hold the same in position to maintain the said chasers in their advanced positions, the said L-shaped latch-member having one arm extendingY substantially radially with respect to the die head structure and another arm extending in substantial parallelism with the axis thereof and over the exterior of the said Chaser-operating member.

2. A self-opening die head including in combination: a Chaser-carrying member; chasers movably mounted in the said Chaser-carrying member; an oscillating Chaser-operating member associated With the said Chaser-carrying member and operatively connected to the said chasers for controlling the movement thereof; springmeans urging the said Chaser-operating member into position to retire the said chasers; a releasable L-shaped latch-member bodily movable with respect to the said chaser-operating member andhaving a portion engageable with a portion of the latter to releasably hold the same in position to maintain the said chasers in their advanced positions, the said yL-shaped latch member having one arm extending substantially radially with respect to the die head structure and another arm extending in substantial parallelism with the axis thereof and over the exterior of the said Chaser-operating member; and a tripping-member carried by the arm of the said L-shaped latch-member which extends over the said chaser-operating member. the said tripping-member being adjustable forwardly and backwardly with respect to the said arm and designed and adapted for engagement with a tripping abutment.

3. A self-opening die head including in combination: a Chaser-carrying member; chasers movably mounted in the said Chaser-carrying member; an oscillating Chaser-operating member associated with the said Chaser-carrying member and operatively connected .to the said chasers for 'controlling the movement thereof; spring-means urging the said Chaser-operating member intoposition to retirel the said chasers; a releasable L-shaped latch-member bodily movable with respect to the said Chaser-operating member and having a portion engageable with a portion of the latter to releasably hold the same in position to maintain the said chasers in their advanced positions, the said L-shaped latchmember having one arm extending substantially radially with respect to the die head structure and another arm extending in substantial parallelism with the axis thereof and over the exterior of the said Chaser-operating member; and a tripping-screw extending in substantial parallelism with the axis of the die head and threadedly-connected to the'arm of the said L-shaped -latch-membenwhich extends over the said cha-ser-operating-memben inposition to engage With an external tripping abutment.

4. A self-opening die head including in4 combination: a Chaser-carrying member; chasers Inovably mounted in the said Chaser-carrying member; an oscillating Chaser-operating member associated with the said chaser-carrying-member and operatively connected to 4the said chasers for controlling` the movement thereof; springmeans urging the said Chaser-operating vmember into position to retire the said chasers; a releasable L-shaped latch-member bodily movable With respect to the said Chaser-operating member and having a portion engageable with a portion of the latter to releasably'hold the same in position to maintain the said chasers in their advanced positions, the said L-shaped latchmember having one arm extending radially with respect to the die head structure-and a tubulary arm extenchng in substantial parallelism with the axis of the said Chaser-operating member and over the exterior thereof; and an adjustingscrew threaded into the tubular arm of the said L-shaped latch-member with capacity for adjustment therein and in position to engage with an external abutment. f

5. A self-opening die head comprisingi a Chaser-carrying member; chasers movably mounted in the ysaid Chaser-carrying member;

a Chaser-operating ring mounted with capacity for oscillatory-movement upon the said chasercarrying member in Ia plane substantially perpendicular to the axis of the die head structure; spring-means urging these-id chaser-operating ring to turn into position to retire the 'said chasers; aretaining-plate secured to the said Chaser-carrying member in position to hold the said Chaser-operating ring thereon against axial displacement; and an L-shaped releasable latchmember having aportion extending through the said retaining-plate'into position to engage a portion of the said chaser-operating ring to hold the same in position to maintain the said chasers in their advanced positions. the said I -shaped latch-member being also provided with means extending forwardly over the *exterior periphery of the said oscillating chaser-operating ring in position to be engaged by an` external abutment.

6. A self-opening die head comprising: a Chaser-carrying member; chasers movably mounted in the said chaser-carrying member; a Chaser-operating ring mounted with capacity for oscillatory-movement upon the .said chasercarrying member in a plane substantially perpendicular to the-axis of the die head structure; spring-means urging the said Chaser-operating ring to turn into position to retire the Asaid chasersg-a retaining-plate secured tothe said Chaser-carrying member in position to hold the said Chaser-operating ring thereon against axial vdisplacement and provided with an eccentric tubular-portion extending over the said chaseroperating ring; and a releasable latch-member having portion moving in the tubular-portion of the said retaining-'plate and also having a portion engageable with a portion of the said Chaser-operating ring to releasably hold the same in position to maintain'the said chasers in their advanced positions.

7. A self-opening die head comprising: a chaser-carrying member; chasers movably mounted in the said Chaser-carrying member;-

a chaser-operating'ring mounted with capacity for oscillatory-movement upon the said` chasercarrying member in a plane substantially perpendicular.- to the axis. ofthe .die head structure; spring-means urging the said Chaser-operating ring to turn into position to lretire thev saidchasers; a retaining-plate secured to the said Chaser-carrying member in position to hold the saidchaser-operating ring thereon against axial displacement and provided with a tubular-portion v .extending over the said chaser-operai'ing ring; and a releasable latch-member having a portion moving in the tubular-portion of the said retaining-plate vand also having a portion extending through thesaid retaining-plate into position' to engage a portion of 'the Chaser-operating member to hold the same in position to maintain 'the said chasers in their advanced positions.

8. A lself-opening die head comprising: a chaser-carrying y member; 'chasers movably Vmounted in the said chaser-.carrying member;

a Chaser-operating ring mounted With capacityv Chaser-carrying member lat the .rear of andin n position to hold the said 'Chaser-operating ring thereon against axial displacement and having a tubular-portion extending forwardlyy overjthe said Chaser-operating ring; and a releasable latch-member having. a portion movable in the tubular-portion of the said retaining-plate, the said latch-member also having a portion located inwardlyyvithrespect to its said tubular-portion and extending forwardly through the said retaining-plate into. position to engage a portion ofthe said Chaser-operating ringto hold ythe same in position to maintain the said chasers in their advanced positions.

9. A self-opening diefhead comprising: avv

pendicular to the axis ofthe die head structure;l

spring-means urging the said Chaser-operating ring to turn vinto position to retire the said chasers; `a retaining-plate secured to the. said chaser-carrying member 'in position to hold the said Chaser-operating ring thereon against axial displacement and having a tubular-portion extending forwardlyover the said Chaser-oper-` ating ri'ng; a releasable latch-member having an internally-threaded tubular-portion movable in the tubular-portion of .thevsaid retaining# plate, the said latch-member also having a portion vengageable with a portion of lthe said l.

f6.0 tionV to maintain the said 4chasers in their adchaser-operating ring. to hold" the same in posi- Vanced. positions;' and an adjusting-screw threaded into the tubular-portion of tl'iesaidv latch-member with capacity lfor axial adjustment thereiny and in position to engage With an external abutment. n

104A self-opening die heady comprising;v al

Chaser-carrying member; chasers movably mounted in the said Chaser-carrying member; a Chaser-operating ring mounted with capacity for oscillatory-movement upon the said Chaser carrying member in` a' plane substantially. perpendicular to the axis ofthe die head structure; l

spring-means urging the said Chaser-operating i ring toturn into position to retirev the said chasers; a retaining-plate secured to the vsaid Chaser-carrying member in position to hold the `said chaser-operating ring thereon against axial displacement and having a tubular-portion extending forwardly over the said Chaser-operating ring; a releasable latch-member having a tubular-portion movable in the tubular-portion of the said retaining-plate, the said latch-member also having a portion located inwardly with respect to its said tubular-portion andextending forwardly through the said retaining-plate into position toengage a portion of the said Chaser-operating ring to hold the same in position to maintain the said chasers in their advanced positions; and an adjusting-screw extending throughthe tubular-portion of the said latch-member and projecting from both ends thereof with capacity for axial adjustment there-` in and in position to engage with a trippingabutment.

V 11. A self-opening die head comprising: a Chaser-carrying member; chasers movably mounted in the said Chaser-carrying member; a Chaser-operating ring mounted with capacity for oscillatory-movement upon the said chasercarrying member in a plane substantially perpendicular to the axis of the die head structure; spring-means urging the said Chaser-operating ring to turn into position lto retire the said chasers; a retaining-plate secured to the said Chaser-carrying member in position to hold the said Chaser-operating ring thereon against axial displacement and having a tubular-portion extending forwardly over the said Chaser-operating ring; a releasable latch-member having a tubular-portion movable in the tubular-portion of the said retaining-plate, the said latch-member also having a portion engageable with a portion of the said Chaser-operating ring to hold the same in position to maintain the said chasers in their advanced positions; and a latch-spring located within the tubular-portion of the said retaining-plate and yieldingly urging the said latch-member into position` to latch the said Chaser-operating ring.

12. A self-opening die head comprising: a Chaser-carrying member; chasers movably mounted in the said Chaser-carrying member; a Chaser-operating ring mounted with capacity for oscillatory-movement upon the said chasercarrying member in a plane substantially perpendicular to the axis of the die head structure; spring-means urging the said Chaser-operating ring to turn into position to retire the said chasers; a retaining-plate secured to the said Chaser-carrying member in position to hold the said Chaser-operating ring thereon against axial displacement and having a tubular-portion extending forwardly over the said Chaser-operating ring; a releasable latch-member having a portion movable in the tubular-portion of the said retaining-plate, the said latch-member also having a portion engageable with a portion of the said Chaser-operating `ring to hold the same in position to maintain the said chasers in their advanced positions; a tubular spring-plunger movable in the tubular-portion of the said retaining-plate and surrounding the portion of the said latch-member which is movable therein; and a latch-spring housed within the tubularportion of the said retaining-plate and thrusting against the said tubular spring-plunger to yieldingly urge the said latch-member into position to restrain the said Chaser-operating ring.

13. A self-opening die head comprising: a

mounting-member; a Chaser-carrying member carried by the said mounting-member with capacity for axial movement with respect thereto; chasers movably mounted in the said chasercarrying member; an oscillating Chaser-operating member carried by the said Chaser-carrying member with capacity for oscillatory-movement in a planev substantially perpendicular to the axis of the said Chaser-carrying member; springmeans urging the said chaser-operating member into position to retire the said chasers; and an L-shaped releasable latch-member bodily movable with respect to the said Chaser-operating member and having a portion engageable with a portion of the latter to releasably hold the 'l same in position to maintain the said chasers in their advanced positions, the said L-shaped latch-member having one arm extending substantially radially with respect to the die head structure and another arm extending in substantial parallelism with the axis thereof and over the exterior of the said Chaser-operating member.

14. A self-opening die head comprising: a,y

a Chaser-carrying member Chaser-operating member and having a portion engageable with a portion of the latter to releasably hold the same in position to maintain the said chasers in their advanced positions, the said L-shaped latch-member having one arm extending substantially radially with respect to the die head structure and another arm extending in substantial parallelism with the axis thereof and over the exterior of the said Chaser-operating member;'and a tripp-ing-screw projecting rearwardly from the said L-shaped latch-member into position to be engaged by a portieri of the said retaining-plate to halt the relative forward movement of the said latch-member when the said Chaser-carrying member is moved forwardly with respect to the said mounting-member by forward draft exerted by the work being threaded, to effect the release of the said Chaser-operating member.

15. A self-opening die head comprising: a. mounting-member; a Chaser-carrying member carried by the said mounting-member with capacity for axial movement with respect thereto: chasers movably mounted in the said chasercarrying member; an oscillating Chaser-operating member carried by the said chaser-carrying member with capacity for oscillatory-movement in a plane substantially perpendicular to the axis of the said chaser-carrying member; springmeans urging the said Chaser-operating member into position to retire the said chasers; a latchmember having projecting portions extending in parallel relation from an arm thereof, one of the said projecting portions releasably holding the said Chaser-operating member in position toi maintain the said chasers in their advanced posi- 2,197;sse o' tions; spring-means urging the said Chaser-carrying member rearwardly with respect to the and second spring-v said mounting-member; means of relatively-limited scope-of-movement and urging the said Chaser-carrying member for`` Wardly with respect to the said mounting-member and providing a cushion receiving the initial thrust upon the said yChaser-carrying member voccurring as avresult ofthe engagement of th carried by the `said mounting-member with ca-v pacity for axial movement with respect thereto; chasers movably mounted in the said chasercarrying member; an oscillating chaser-operating member carried by the said Chaser-carrying member with capacity for oscillatory-movement in a plane substantially perpendicular to the axis of thev said Chaser-carrying member; springmeans urging the said chaser-operating member into position to retire the said chasers; a latchmember having projecting portions -extending in parallel relation froman arm thereof, one of the said projecting portionsreleasably holding the said Chaser-operating Vvmember in position t0- maintain the said chasers in their advanced posif tions; spring-,means urging the said Chaser-carrying member rearwardly with respect to the said c mountingmember; second spring-means of relay tively-limited scope-of -movement andurging the saidchaserfcarrying member forwardly with respect to thesaid mounting-member and providing a cushion receiving the initial thrust upon the said chaser-carrying member occurring as a re-v sultof the engagement of the said chasers with the Work; and a limiting-screw extendable between the saidchaser-carrying member and the said mounting-member to form a positive stop for the former and to eliminate the action of the said second spring-means;

' y fALBERT F. BREITENSTEIN. 

